Compressor.



Y W. E. VER PLANCK.

COMPRESSOR.

APPUCATION HLED SEPT. I. 1915.

Patented Oct. 9, I917.

2 SHEETSSHEET 1.

Inve ntor-z Hisaqtol-nqy.

UNITED STATES PATENT OFFICE.

WILLIAM EVERETT VER PLANCK, OE ERIE, PENNSYLVANIA, ASSIGNOR TO GENERAL 4 ELECTRIC COMPANY A CORPORATION OF NEW YORK.

COMPRESSOR.

Specification of Letters Patent.

Patented Oct. 9, 1917.

Application filed September 1, 1915. Serial no. 48,445.

siding at Erie, in the county of Erie, State of Pennsylvania, have invented certain new and useful Improvements in Compressors, of which the following is a specification.

sors and has for its object to provide "an improved structure in a compressor of the reciprocating type, the improvements be ng particularly applicable to compressors 1ntended to handle large volumes at low pressures. One application of my invention is as a pump for supplying the scavenging a1r to an internal combustion engine, and in the accompanying drawing I have so illustrated it, but it will be understood'that it is not limited thereto.

In the accompanying drawing Figure 1 is a vertical section through the compressor structure of an internal combustion engine and illustrating a'scavenging pump embodying my invention, and Figs. 2 to 5 inclusive are sectional views through the scavenging pump taken at right angles to Fig.1 and showing different relative. positions of the moving parts.

Referring to the drawing, 10 indicates a crank case which-may be common to the engine and compressor (the engine not being shown), and 11 indicates a crank shaft supported in suitable bearings 11 therein. Mounted on the crank case is the annular wall 12 which forms the outer cylinder wall of the scavenging pump, and surrounding the wall 12 is a Wall 13 which defines an admission chamber 14 and a wall 15 which defines a discharge chamber 16. The admission chamber 14 communicates with the atmosphere or other source of supply by way of conduit 17 which extends across the chamber 16 andhas a suitable screen 18' at its mouth to prevent the entrance of foreign the scavenging pump is shown as being combined in the same structure as the compressor which furnishes the blast air and starting air for the engine. 24 indicates the cylinder structure for the two stages of the compressor, it being mounted on cylinder wall 12,

and 25 and 26 indicate the pistons. The The present invention relates to compres- H "'26 1s formed integral with it. The further piston 25 is of the trunk type and the piston details of structure of this compressor form no part of the present invention so additional description and illustration is considered unnecessary. 27 is a connecting rod connecting these pistons to a crank 28 on the crank shaft 11. Surrounding the connecting rod and having a sliding fit with the inner surface of the trunk piston isan innercylinder wall 29 which, with the outer wall 12, defines an annular cylinder 30 for the scavenging pump. Formed integral'with the lower edge oftrunk piston 25 is a flange 31 which constitutes the piston of the scavenging pump, the wall 32 which is a part of the compressor cylinder structure 24 and the wall 33 formed integral with the inner cylinder wall 29 constituting the-heads of the cylinder. Between. the piston 31 and the wall 12 is a sleeve valve 34 ,which controls the admission of air or other substancebeinfg pumped to-and from cylinder 30. Itzis pre erably formed integral with the head 33 and inner cylinder'wall' 29, and is together with such parts connected by rods 35 to eccentrics 36 on the crank shaft. The sleeve valve has two sets of ports 37 and 38 which cotiperate with the ports 20, 22 and 21, 23 respectively. 39, 40, 41 and 42 indicate suitable packings arranged between the relatively moving parts. 43 and 44 indicate the cylinder and piston of a compressor which is operated from the crank shaft 11, and is illustrated as being provided with air from the discharge side of the scavenging pump byway of passage 45. This compressor forms no part of the present invention, being only. a part of the system in connection with which my improved pump is used, and further de just completed its downward stroke and the sleeve valve 34 is shown as having been moved part way by its eccentrics 36 to cover valve to reverse position. sition is shown in Fi 5 where the piston s shown at the beginning of its down stroke.

the ports 20' and'23 and uncover the ports 22 and 21. The direction of rotation of the crank shaft is indicated by the arrows applied to the crank shaft in each of the views.

Referring now to Fig. 3 the sleeve valve has completed its movement and the piston 31 is started on its upward stroke. The air within the cylinder 30 is discharged from above the piston through ports 37 and 22 into the discharge chamber 16, at the same time a fresh charge of air is being sucked in from the chamber I l through the ports 21 and 38. As has already been stated, the admission. and discharge ports entirely surround the cylinder wall. This gives the maximum size of ports so that a free suction results. At the same time, it does not necessitate increasing the clearance. This feature is particularly advantageous in connection with a low pressure pump handling a considerable volume of air, as a quite large percentage of the loss in such apump is due to the friction losses in the ports.

Referring now to Fig. l, the piston is shown as having completed its out stroke and the eccentrics 36 are shifting the sleeve This reverse po- I-Iere, the admission ports 20 are in alinementv with the ports 37 in the sleeve valve and the discharge ports 23 are in alinement with the ports 38 in the sleeve valve. It will thus be seen that the sleeve valve operates to alternately connect the spaces upon the respective sides of the piston 31 to the admission and exhaust chambers respectively as is necessary in the operation of a double acting pump.

- It will be noted that the discharge ports 22 and 23 are at the outer and. inner ends of the cylinder wall and that the inlet ports are inside of them. This arrangement has advantage in connection with a compressor having splash lubrication in that any leakage of oil by the ring 40 is prevented by the pressure in discharge port rather than being sucked into the cylinder as would be the case were it an admission port.

'As will be seen, particularly from Figs. 2 and 4, by my improved arrangement I ob tain a very close clearance at both ends of the stroke of the piston 31. This results in a high volumetric efficiency, and is possible due to the advantageous distribution of the admission and discharge ports in connection with the sleeve Valve.

In accordance with the provisions of the patent statutes, I have described the principle of operation of my invention together with the apparatus which I now consider to represent the best embodiment thereof, but I desire to have it understood that the apparatus shown is only illustrative, and that the invention can be carried. out by other means.

What I claim as new and desire to secure by Letters Patent of the United btates, is

1. In a compressor, the combination of two concentric walls forming between them an annular cylinder, an annular piston therein, a crank shaft, a rod connecting the piston thereto, admission and exhaust ports in one of said annular walls, a sleeve valve controlling said ports, an eccentric on the cam shaft, and means connecting it to the sleeve valve.

2. In a compressor, the combination of two concentric walls forming between them an annular cylinder, a trunk piston within which the inner concentric wall fits, said trunk piston having an annular flange which forms the piston of the compressor, a crank shaft, a rod connecting the trunk piston to a crank on such shaft, admission and exhaust ports in one of said concentric walls, a sleeve valve for controlling them, an eccentric on the cam shaft, and means connecting it to the sleeve valve.

3. In a compressor, the combination of two concentric walls forming between them an annular cylinder, a trunk piston within which the inner concentric wall fits, said trunk piston having an annular flange which forms the piston of the compressor, a crank shaft, a rod connecting the trunk piston to a crank on such shaft, admission and discharge ports in the outer concentric wall, a sleeve valve formed integral with said inner concentric wall and located between the piston of the compressor and the outer concentric wall for controlling said ports, an eccentric on the cam shaft, and means connecting it to the inner concentric wall and the sleeve valve.

In witness whereof, I have hereunto set my hand this 30th day of August, 1915.

WILLIAM EVERETT VER PLANGK. 

